工业有机合成》(第九章).ppt

1 Chapter 9 Oxidation-Reduction Reactions and their Industrial Possibilities u 9.1 General Introduction of oxidation 1. The reaction types +O in organic compounds both -H and +O in organic compounds organic compounds oxidation and decomposition organic compounds ammoniac-oxidized Epoxy-ethane Cyano-compound 2 2. can be made by the oxidation reactions ROH Epoxy-compound Cyano-compound 3 3. The general features of the oxidation reactions 1）The oxidizing agents The gas phase oxygen O2 cheaper, without the instrument damage, but lower oxidizing ability need catalytic. Oxygen atom O generated from the chemical oxidizing agents, high oxidizing- abilities, high selection, mild reaction conditions, but high cost. 4 2) Strong heat releasing reactions 3) Unconverted reaction 4) Multi-reaction ways and with by-reactions In order to obtained the target oxidized compound, the suitable way must be selected 5 The air is flowed into the organic compound in liquid phase under the action of catalytic, then the compound is oxidized, this kind of reaction has been called the air liquid phase oxidation reaction u 9.2 Air liquid phase oxidation reactions Definition for the reaction requirement A: special reactor：air-flowing-style reactor B: catalytic (soluble in the organic liquid) 6 n 9.2.1 The reaction process Some organic compounds O2 Automatic react The reaction very slow Increasing the reaction Catalytic or initiation agent 7 The automatic oxidation Typical free radical chain-style reaction B: Chain transfer C: Chain termination A: Chain initiation 8 1. The chain initiation 9 2. The Chain transfer 10 3. The chain termination 11 n 9.2.2 The elements of influence the automatic oxidation 1. Initiation agents and catalytic 1) + initiation agent the organic compound to be oxidized easy 2) + catalytic ( the transitional metal ion, such as: Co2+ , Mn2+, Fe3+, V5+ etc.) the activation energy of the organic compound to be reduced 12 2. The influence of the oxidized organic compounds structure The organic compounds C-H bonds to be broken are relative to the energy of these bonds The energy order as follows: The third C-H the second C-H the first C-H, thus , the oxidation first occur at the third C atom. 13 3.The influence of the anti-reactive （阻化）agents The anti-reactive agents can react with the free radicals to form the stable compounds, and to result the chain termination; and few quantity of the agents can also make the oxidation process slowing down. 14 The stronger anti-reactive agents including: a: phenolic; b: amine; c: quinone;d: alkene such as: 15 4. The influence of the degree of the oxidation （氧化深度） For most of the automatic oxidation, particularly to synthesize organic peroxides, aldehydes and ketones: In order to overcome this problem, the conversation rate should be kept at lower level, as the result the oxidation could be with a higher reaction speed and a higher selective. with the conversation rate （转化率） increasing the by-products （containing the anti-reactive agents) increased the oxidation speeds slowed down the by-reaction can also cause the oxidized compound to be decomposed further. 16 Although the conversation rate on-one-way is unlikely higher, but the higher selective could be kept, and the unreacted raw material could also to be re-used circularly, therefore, the general productivity is higher. on special situation, for the oxidation with some stable oxidized products, such as: carboxylic acid (羧酸) 17 Benzoic acid as the food additive, intermediate of dyes, drugs and perfumes etc pay a very important role in the fine chemical industry, the common way to synthesis this compound to employ toluene and air : n 9.3.2 Industrial example 18 The industrial chemical process of synthesis benzoic aci